Optimiser et stabiliser la composition protéique des graines de légumineuses

International audience

A holistic overview of the impact of sulfur deficiency in pea facing water deficit

We report on the interplay between water deficit and sulfur deficiency, two constraints that are increasingly faced by crops due to climate change and low-input agricultural practices. In particular, we aim at better understanding the role of sulfur nutrition in the trade-off between seed quality establishment and plant stress tolerance in pea (Pisum sativum L.), a grain legume crop which has a pivotal role to play in both agroecological and food transitions. Like other legumes, pea is able to accumulate large amounts of seed proteins even in the absence of nitrogen fertilizers thanks to its symbiosis with N2-fixing soil bacteria. In this study, we deprived pea plants (cv. Caméor) of sulfur…

Plant genotype: a lever in the interactions between plant and its associated rhizosphere microbiome

International audience; In the context of highly pressured agricultural production using low levels of inputs, cropping strategies could take advantage of existing plant-microbiome interactions that can improve both plant growth and health. We believe that plant genetics can provide some clues to better understand the mechanisms underlying microbiome recruitment by the plant.The aims of this work were (i) to assess plant genotype effect on the rhizosphere bacterial communities in relation to the plant nutritional strategies for a core collection of 155 genotypes of Medicago truncatula and (ii) to highlight the genetic determinisms potentially associated in these interactions. To achieve the…

Use of translational genomics to identify genes important for legume seed filling

International audience; Translational genomics, i.e., the transfer of genetic information from model species to cultivated crops, is on the brink of revolutionizing plant breeding. The recent publication of genomic sequences for several cultivated legumes is also accelerating this process. For pea, recent highthroughput RNA sequencing, and the prospect of a genome sequencing project, will further accelerate the transfer of information from the Medicago truncatula model to the cultivated crop. We have been using genomics approaches with Medicago as a tool to identify key genes determining seed yield and composition in closely related legumes. Analyses of the proteome and transcriptome of the…

Characterization of the biosynthesis of saponins during seed development in peas (Pisum sativum)

National audience; The use of pulses as ingredients for the production of food products rich in plant proteins is increasing. However, protein fractions prepared from pea or other pulses contain significant amounts of saponins, glycosylated triterpenes which can impart a bitter taste to the final food product. Bitter flavours are currently either removed by energy-requiring physico-chemical treatments or masked by additives. We are in the process of identifying and characterizing the genes involved in saponin biosynthesis during pea seed development, with the objective of identifying mutants in which seed saponins no longer accumulate. To do this we have applied a saponin extraction protoco…

Induced mutations in the TI1 gene encoding a major double-headed protease inhibitor in Pisum sativum L. can reduce significantly the inhibition of target enzymes

BAP GEAPSI; International audience; Trypsin / chymotrypsin inhibitors in the seeds of many legume crop species are regarded as antinutritional proteins often leading to a requirement for heat-treatment of seed products prior to their use in feed. A TILLING resource developed in Pisum sativum L. (pea) was exploited to identify mutants in the major seed-expressed trypsin / chymotrypsin inhibitor gene, TI1, where the inhibition of either or both of the target enzymes may be reduced. Three lines with missense mutations in TI1, predicted to affect activity through alteration of (a) a conserved cysteine residue, (b) the P1′ serine within the active site of the chymotrypsin inhibitory domain or (c…

Dissection of pea responses to water stress during seed filling identifies candidate genes for drought tolerance

International audience; Given their ability to fix atmospheric nitrogen, legumes are pivotal to the development of sustainable agriculture in Europe as a source of protein for food and feed. Pea (Pisum sativum) is currently the leading grain legume crop in France and major efforts are being made to reintroduce legumes as protein crops in Europe. However, instability of seed yield and quality due to environmental fluctuations still represent a real barrier for the development of these cultures, and breeding for stable yields is needed. In pea, drought stress occurring during the reproductive phase can greatly affect seed yield and quality. We investigated the response of pea plants (var. Cam…

Vers des variétés de légumineuses à graines mieux adaptées à l’alimentation humaine

National audience; Les légumineuses font partie des aliments de l’homme depuis les premiers âges de l’agriculture et sont très présentes dans les repas des pays en développement. Outre un apport en réserves carbonées qui selon les espèces sont à dominante d’amidons ou de lipides, ces graines riches en protéines enrichissent les régimes en acides aminés très complémentaires de ceux des céréales. L’aptitude des racines de légumineuses à établir une symbiose avec des bactéries rhizobiacées qui leur permet d’utiliser l’azote de l’air comme principale ressource d’azote, combinée à une consommation directe par l’homme de ces graines qui permet de diminuer la consommation de viandes, constituent u…

Role of vacuolar sulfate in nutritional quality of pea seeds

Grain legumes have a key role to play in both agroecological and food transitions. Indeed, these plants are able to accumulate large amounts of proteins in their seeds even in the absence of nitrogen fertilization thanks to symbiotic N2 fixation in the root nodules. However, legumes are exposed to abiotic stresses, including nutrient deficiencies, making it important to optimize nutrient use efficiency for maintaining seed protein content and quality. Seed protein quality refers to the ability of the seed proteins to meet the body’s requirements for essential amino acids. It strongly depends on the amino acid balance, which determines protein digestibility. In pea (Pisum sativum) seeds, met…

High-troughput TILLING to identify symbiosis-related plant gene function in arbuscular mycorrhiza

International audience

Use of translational genomics to identify genes important for legume seed development

BAP Pôle GEAPSI; International audience; We have exploited the extensive synteny between the model legume Medicago truncatula and the cultivated garden pea, Pisumsativum, to identify loci controlling seed filling and seedcomposition in the crop species. QTLs for these traits are mapped by analyzing variation with in collections of recombinant inbred lines. Candidate genes with in the QTL intervals are identified by reference to the M.truncatula genomic sequence. This approach was used to uncover an endosperm subtilase that is associated with syntenic seed weight QTLs in Medicago and pea, and we discuss the possible role played by this enzyme in contributing to final seed weight.

The role of sulfur in the control of seed quality traits in legumes: from model to crop species

National audience; voir pdf

Regulation of legume seed size by an endosperm-expressed transcription factor

BAP Pôle GEAPSI; International audience; There are numerous reports of transcription factors (TFs) which are implicated in the control of seed size and seed composition. We have identified, using a platform of TF sequences derived from the Medicago truncatula genome sequence, a class of TFs specifically expressed during the seed filling stage. One such TF, DASH, was shown to be confined to the developing endosperm. We investigated the role played by DASH through analysis of mutant alleles. These give rise to seed-lethal or near-lethal phenotypes, with degeneration of the endosperm and arrested embryo development. The relation of this phenotype to seed auxin action was investigated.

β-Amyrin Synthase1 Controls the Accumulation of the Major Saponins Present in Pea (Pisum sativum)

Abstract The use of pulses as ingredients for the production of food products rich in plant proteins is increasing. However, protein fractions prepared from pea or other pulses contain significant amounts of saponins, glycosylated triterpenes that can impart an undesirable bitter taste when used as an ingredient in foodstuffs. In this article, we describe the identification and characterization of a gene involved in saponin biosynthesis during pea seed development, by screening mutants obtained from two Pisum sativum TILLING (Targeting Induced Local Lesions IN Genomes) populations in two different genetic backgrounds. The mutations studied are located in a gene designated PsBAS1 (β-amyrin s…

L'amélioration de la qualité de la graine dans toutes ses dimensions, par le levier génétique

Les légumineuses sont capables d’accumuler des quantités importantes de protéines dans leurs graines même en l’absence d’engrais azoté, ce qui fait d’elles des espèces à haut potentiel pour relever les défis alimentaires et accompagner la transition agroécologique. Des avancées génétiques ont permis de réduire la présence de certains facteurs « anti-nutritionnels » dans les graines de pois et de féverole (exemple des variétés pauvres en tanins, en inhibiteurs trypsiques, ou en vicine et convicine). Afin de promouvoir l’utilisation de ces graines en alimentation humaine, il est nécessaire d’aller plus loin dans l’amélioration de leur valeur nutritionnelle, en termes de teneur et composition …

GWAS results in response to sulfur deficiency

Sulfate transporters in the plant’s response to drought and salinity: regulation and possible functions

International audience; Drought and salinity are two frequently combined abiotic stresses that affect plant growth, development, and crop productivity. Sulfate, and molecules derived from this anion such as glutathione, play important roles in the intrinsic responses of plants to such abiotic stresses. Therefore, understanding how plants facing environmental constraints re-equilibrate the flux of sulfate between and within different tissues might uncover perspectives for improving tolerance against abiotic stresses. In this review, we took advantage of genomics and post-genomics resources available in Arabidopsis thaliana and in the model legume species Medicago truncatula to highlight and …

Importance des voies de recyclage de la méthionine dans le contrôle de la plasticité de la composition protéique des graines

International audience; La production de protéines végétales en France et en Europe nécessite de fournir des outils d’aide à la sélection de variétés de légumineuses produisant des graines de meilleure valeur nutritionnelle possible. Bien que certains constituants réputés antinutritionnels aient été réduits dans les graines des variétés de légumineuses, la fraction protéique reste à améliorer et à stabiliser pour d’avantage d’équilibre en acides aminés. Cet enjeu nécessite d’identifier les gènes contrôlant la composition protéique des graines et sa plasticité vis-à-vis de l’environnement. Une approche de génétique d’association à l’échelle du génome (GWAS) appliquée à 200 écotypes de Medica…

Recherche des gènes contrôlant la plasticité de la composition protéique des graines vis-à-vis de l’environnement par une approche GWAS chez Medicago truncatula

National audience; Les légumineuses sont capables de produire des graines riches en protéines en l’absence d’apports azotés grâce aux symbioses qu’elles établissent avec des bactéries fixatrices d’azote de l’air. Riches en lysine, ces protéines sont utilisées pour la nutrition humaine et l’alimentation animale. Cependant, les instabilités de la teneur et de la composition protéique des graines causées par les variations environnementales limitent l’adoption des légumineuses en Europe. Afin de promouvoir leur culture, il est nécessaire d’optimiser et de stabiliser la quantité et la qualité de cette fraction protéique. Nous avons étudié la plasticité de la teneur et de la composition protéiqu…

Importance du sulfate vacuolaire pour l’établissement du rendement et de la qualité des graines de pois

Les graines de pois constituent un aliment sain et nourrissant, notamment de par leur forte teneur en protéines (environ 25%). La qualité nutritionnelle de ces protéines est néanmoins limitée par leur faible proportion en acides aminés soufrés (AAS) : cystéine et méthionine. L’objectif était d’étudier la contribution du stock de sulfate contenu dans les vacuoles à l’élaboration du rendement et de la qualité des graines, notamment la synthèse des AAS. Nous avons ciblé l’unique gène SULTR4 de pois qui code un transporteur permettant l’efflux de sulfate de la vacuole vers le cytosol. Après avoir confirmé sa localisation à la membrane vacuolaire, nous avons recherché des mutants de pois pour ce…

The roles of the embryo-surrounding tissues in regulating Medicago truncatula seed filling

National audience

Genetic determinants of seed protein plasticity in response to the environment in Medicago truncatula

As the frequency of extreme environmental events is expected to increase with climate change, identifying candidate genes for stabilizing the protein composition of legume seeds or optimizing this in a given environment is increasingly important. To elucidate the genetic determinants of seed protein plasticity, major seed proteins from 200 ecotypes of Medicago truncatula grown in four contrasting environments were quantified after one-dimensional electrophoresis. The plasticity index of these proteins was recorded for each genotype as the slope of Finlay and Wilkinson's regression and then used for genome-wide association studies (GWASs), enabling the identification of candidate genes for d…

The pea sulfate transporter, PsSULTR4, contributes to seed yield and quality

To investigate the role of vacuolar sulfate in seed yield and quality, we have targeted the single pea SULTR4 gene (PsSULTR4), which encodes a transporter homologous to Arabidopsis SULTR4;1 and 4;2 that allow sulfate efflux from the vacuole to the cytosol. By simulating the 3D structure of PsSULTR4, we observed that it is similar to that of SULTR4;1 in Arabidopsis. Furthermore, a phylogenetic analysis revealed a high level of conservation of SULTR4 protein motifs across land species. A fluorescent protein fusion experiment confirmed that PsSULTR4 localizes to the vacuolar membrane.Five sultr4 mutants were identified by TILLING (Targeting Induced Local Lesions IN Genomes), two of which showe…

Role of vacuolar sulfate in the nutritional quality of pea seeds

Legumes have a key role to play in both agroecological and food transitions due to their ability to accumulate large amountsof seed proteins without nitrogen fertilization thanks to symbiotic N2 fixation in the root nodules. However, in agroecologicalsystems, legumes are more exposed to nutrient deficiencies, including sulfur deficiency, than in conventional systems, makingit important to optimize nutrient use efficiency for maintain seed protein quality, in particular the level of (semi) essentialamino acids like methionine and cysteine. These sulfur-containing amino acids are synthetized through the sulfur metabolicpathway starting from sulfate reduction. Sulfate is taken up from the soil…

Genetic diversity for seed protein composition in Meticago truncatula

International audience

Optimizing and stabilizing protein composition of legume seeds

International audience

Regulation of the plasticity of longevity upon drought in Medicago truncatula involves the cryptochrome-interacting bHLH49 transcription factor

International audience

Pea TILLING platform

Includes the Final Dissemination Event of the EU Grain Legumes Integrated Project; International audience

Déterminisme génétique de la composition protéique des graines de légumineuses et de sa plasticité vis-à-vis de l’environnement

Les légumineuses sont capables de produire des graines riches en protéines sans apport d’engrais azoté grâce à la symbiose racinaire avec des bactéries du genre rhizobium. Riches en lysine, ces protéines sont utilisées pour l’alimentation des animaux d’élevage et en nutrition humaine. Afin de promouvoir la culture des légumineuses, il est nécessaire d’optimiser et de stabiliser la qualité de cette fraction protéique. L’objectif de ma thèse est de mettre en évidence les déterminismes génétiques sous-jacents à la teneur et à la composition protéique des graines de légumineuses ainsi qu’à la plasticité de ces composantes vis-à-vis de l’environnement. Afin de répondre à cet objectif, l’approche…

Déterminisme génétique de la plasticité de la composition protéique des graines de légumineuses vis-à-vis de l'environnement

National audience; voir pdf

Adapter la composition protéique des graines de légumineuses en fonction des usages

National audience

L'accumulation des protéines dans les graines de légumineuses

The agroecological benefits of legumes and the renewed interest in the consumption of vegetable proteins stimulate researches on cognitive and applied aspects of seed biology aiming at optimizing protein composition of legume seeds. This article presents the state of knowledge on the genetic and environmental control of the accumulation of major proteins found in legume seeds, with a view to developing varieties with improved nutritional seed quality. It also shows how high-throughput genomics and post-genomics data, along with translational research aiming at transferring knowledge between model and crop species, can accelerate the identification of genes controlling the accumulation of st…

La génétique au service du goût : caractérisation de mutants pour l'accumulation de saponines et l'activité lipoxygènase dans la graines de pois (Pisum sativum)

International audience

Legume adaptation to sulfur deficiency

BAPSPEEAGEAPSIIPM; Because sulfur-deficiency represents an agronomic issue for crops and notably for the quality of legume products, it is necessary to provide sulfur fertilizers according to crop sulfur needs along with improving sulfur use efficiency. To achieve this goal, increased knowledge of how plants respond to sulfur-deficiency is required. We subjected Medicago truncatula, a model legume species, to sulfur deficiency at different developmental stages and compared yield, nutrient allocation and seed traits. We revealed an impressive plasticity of M. truncatula that varied according to the S-stress period and influenced seed composition and germination. Sulfur deficiency at a mid-ve…

Elucidating the genetic determinism of the plasticity of seed proteins in response to the environment using Medicago truncatula

International audience; Legumes are able to produce high-protein seeds without nitrogen fertilizer through root symbiosis with nitrogen-fixing rhizobia. Rich in lysine, these proteins are used for human nutrition and animal feed. However, instability of seed protein yield and quality due to environmental fluctuations limits the wide adoption of legumes in Europe. Breeding efforts are needed to optimize and stabilize seed nutritional quality. We have studied the plasticity of protein content and composition of seeds from a collection of 200 ecotypes of Medicago truncatula grown under four controlled conditions (optimal, drought, and winter/spring sowing). A quantitative analysis of one-dimen…

TILLING resources in pea: a valuable tool for functional validation

Prod 2019-88t BAP GEAPSI INRA; National audience; Since 2004, two INRA teams (UMR Agroecology Dijon and IJBP, Versailles), both partners of PEAMUST, have created 3 EMS-induced mutant collections in the framework of European or French ANR projects. The genotypes chosen for these collections have specific agronomic traits according to the research subject. For example, the Terese rms3 and -rms4 branched genotypes (Rameau et al., 1997) are well suited to the study of shoot architecture in relation with strigolactone and the lines easy to grow and to backcross in glasshouse conditions. Caméor, an early cultivar with high seed protein content, is the reference genotype for the pea sequencing pro…